Rotary compressors are widely used in electrical appliances such as air conditioners, heaters, and hot water dispensers. As one approach to improve the efficiency of rotary compressors, there has been proposed a technique for suppressing so-called heat loss, i.e., a decrease in efficiency caused by the fact that a refrigerant drawn into a compression chamber (a drawn refrigerant) receives heat from the environment.
A rotary compressor of Patent Literature 1 has a closed space provided in a suction-side portion of a cylinder as a means for suppressing heat reception by a drawn refrigerant. The closed space suppresses heat transfer from a high-temperature refrigerant in a closed casing to the inner wall of the cylinder.